Originally posted by: SystemAdmin

dvar boolean xhorizentalvertical;
float costhorizentalvertical;

minimize sum (i in horizental, j in vertical )cost[i][j]*x[i][j];

subject to {

// one store in each street
forall (i in horizental)
sum (j in vertical)x[i][j]<=1;

forall (j in vertical)
sum (i in horizental)x[i][j]<=1;

//at least 3 miles apart
forall (i in horizental)
forall (j in vertical)
if (x[i][j]!=0)
{
forall (k in horizental)
forall (l in vertical)
if (x[k][l]!=0)
abs (i - k)+ abs (j - l)>=3;
}
I want to put condition on decision var. But an error occur which said that I can not put decision var. in if. May I ask you to help me.

Thanks
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

Decision variables cannot appear in conditionals (see here).
Usually you can get what you want by using logical constraints, in your case probably "implications".
#CPLEXOptimizers
#DecisionOptimization